Saccharification of cellulosic materials, particularly biomass waste products of agriculture, forestry and waste treatment are of great economic and environmental relevance. As part of biomass energy utilization, attempts have been made to obtain ethanol (bioethanol) by hydrolyzing cellulose or hemicellulose, which are major constituents of plants. The hydrolysis products, which include sugars and simple carbohydrates, may then be subjected to further biological and/or chemical conversion to produce fuels or other commodity chemicals. For example, ethanol is utilized as a fuel or mixed into a fuel such as gasoline. Major constituents of plants include, for example, cellulose (a polymer glucose, which is a six-carbon sugar), hemicellulose (a branched polymer of five- and six-carbon sugars), lignin, and starch. Current methods for liberating sugars from lignocellulosic materials, however, are inefficient on a commercial scale based on yields, as well as the water and energy used.
Work from the 1980's on the hydrolysis of β-glycosidic bonds using perfluoronated solid superacid microporous resins, such as Dupont Nafion®, attempted to develop catalytic methods for use in digesting cellulose. Batch reactors and continuous-flow fixed-bed tube reactors were used to demonstrate hydrolysis of cello-oligosaccharides to monomeric sugars; however, these processes were unable to achieve appreciable digestion of cellulose or hemicellulose, and in particular, the crystalline domains of cellulose.
As such, there is an ongoing need for new catalysts that can efficiently generate sugar and sugar-containing products from biomass on a commercially-viable scale.